In the description of the background of the present invention that follows reference is made to certain structures and methods, however, such references should not necessarily be construed as an admission that these structures and methods qualify as prior art under the applicable statutory provisions. Applicants reserve the right to demonstrate that any of the referenced subject matter does not constitute prior art with regard to the present invention.
Known tape measures include tape measures having a metallic measuring blade which is spooled within a casing. The blade is extendable from the casing by pulling its free end. When released, the blade is automatically retracted back into the casing. Typically, this retraction is due to a spring within the casing, for example, a spring connected between the casing and a reel on which the blade spools.
In order to prevent unwanted retraction of the blade during use, it is necessary to maintain the blade in its extended form. This maintenance of extension can be done manually by the user, for example, but this is inconvenient. Usually, a brake is provided which can be operated to prevent the blade from retracting or from extending further.
The brake can act on the reel to prevent spooling and/or unspooling of the blade. Alternatively, the brake can act directly on the blade to prevent movement with respect to the casing. In either case, the brake must exert a considerable force since the blade is usually immobilised by friction. In the case where the brake acts directly on the blade, the brake can press the blade against a portion of the casing.
Typically, a brake is engageable by operation of a button or the like on or in the casing. Alternatively it may be engageable by operation of a slider. In either case, the user normally must exert considerable force to engage and/or disengage the brake since the brake itself must exert considerable force to brake the blade.